The present invention is generally related to polymeric nanoparticles. More particularly, the present invention provides polymeric nanoparticles comprising triblock copolymer chains and optionally diblock copolymer chains. The architecture of the polymeric nanoparticles may be controlled via, for example, by adjusting the size of one or more of the blocks in the triblock copolymer chain and/or by adjusting the ratio of diblock to triblock copolymer chains. The present invention also provides a method for preparing the polymeric nanoparticles and a rubber article with improved physical properties.
Over the past several years, polymeric nanoparticles have attracted increased attention not only in the technical fields such as catalysis, combinatorial chemistry, protein supports, magnets, and photonics, but also in the manufacture of rubbery products such as tires. For example, nanoparticles can modify rubbers by uniformly dispersing throughout a host rubber composition as discrete particles. The physical properties of rubber such as moldability and tenacity can often be improved through such modifications. Moreover, some polymeric nanoparticles may serve as a reinforcement material for rubber. For example, polymer nanostrings are capable of dispersing evenly throughout a rubber composition, while maintaining a degree of entanglement between the individual nano-strings, leading to improved reinforcement over traditional reinforcing fillers.
However, an indiscriminate addition of nanoparticles to rubber may cause degradation of the matrix rubber material. Rather, very careful control and selection of nanoparticles having suitable architecture, size, shape, material composition, and surface chemistry, etc., are needed to improve the rubber matrix characteristics. For example, properties of polymeric nanoparticles made from diblock copolymer chains are controlled by the thermodynamics of diblock copolymers in a selected solvent. The thermodynamic phase diagram of those systems usually depends on two factors, the volume fractions of the components (φi, i=1, 2, 3 . . . ) and the miscibility between them (χijNi parameter between components). Therefore, for a given system, i.e., when the χijNi parameters between components are fixed, the formation of micelle structures depends primarily on the volume fraction of each component (φi, i=1, 2, 3 . . . ). In order to obtain a micelle nanoparticle of desired structure, the concentration or the volume fraction must be controlled. Flexibility of concentration adjustment is usually small due to the underlying thermodynamic laws and the phase diagrams. As such, it cannot provide high flexibility in concentration variations. This could raise unwelcome constraints in industrial processes.
Advantageously, the present invention provides non-spherical polymer nanoparticles comprising triblock copolymer chains, and optionally diblock copolymer chains in a variety of architectures, as well as a flexible process for their manufacture.